Victoria Police said up to $350,000 will be rewarded for any information leading to the arrest and conviction of the man responsible.

"In appropriate cases, the DPP may consider, according to established guidelines, the granting of identification from prosecution to any person who provides information as to the identity of the principal offender or offenders in this matter," a statement read.

Any payment will be subject to a deed of confidentiality prior to it being made.

The offender is described as being 182cm tall with a thin build, light coloured eyes and Caucasian in appearance. At the time, he was wearing dark loose-fitting pants, a dark jumper, runners and a dark coloured balaclava over his face.

Anyone with information is urged to contact Crime Stoppers on 1800 333 000.